61212073L1-5D
Issue 4, August 2004
5
Signal Relay Replacement
Each loop has a cut-through signal relay accessible on
the backplane. The relay ensures data transfer in the
event the NIU3 card fails, is removed, or loses power.
Failure of the relay is determined by process of elimi-
nation. If a loss of signal occurs, and all other param-
eters are satisfactory, then a failed relay is indicated. A
relay replacement kit (P/N 1212072L1) is available
from ADTRAN.
CAUTION
Observe prong configuration on the removed
relay. Relays are polarity sensitive, and
replacement relays must be oriented correctly.
Follow this procedure to replace a failed signal relay:
1. Insert a jumper strap on the posts immediately
adjacent to the suspect relay. This provides a signal
path bypassing the relay.
2. Using an appropriately-sized IC extractor tool, lift
the relay off its socket.
3. Align and insert the replacement relay, taking care
not to bend prongs, and that relay orientation is the
same as the removed relay.
4. Remove the jumper strap.
5. Observe normal operation.
Alarm Relay Replacement
The alarm relay is located adjacent to the alarm wire-
wrap pins on the backplane. The alarm relay output
responds to the card malfunction status on individual
NIU3 cards. If an alarm condition occurs, but an alarm
signal is not present, then a failed alarm relay is
indicated. Follow this procedure to replace a failed
alarm relay:
1. Using an appropriately-sized IC extractor tool, lift
the relay off its socket.
2. Align and insert the replacement relay, taking care
not to bend prongs, and that relay orientation is the
same as the removed relay.
8. SPECIFICATIONS
for shelf specifications.
Table 2. DS3 NIU3 3-Slot Shelf Specifications
Environmental
Operating Temperature
Storage Temperature
Relative Humidity
–40°C to 70°C
(–40°F to 158°F)
–40°C to 85°C
(–40°F to 185°F)
Per GR-63
Physical
Dimensions
Weight
17.5 in. W
7.0 in. D
1.75 in. H
T400 density
12 lb. w/3 NIU3 cards
Power
Volts
Max input current
–48 VDC or ±24 VDC
(nominal)
0.375 A or 0.750 A
(fully loaded)
Compliance
NEBS
UL
FCC
ANSI
Level 3
60950
Part 15, Class A
T1.404
Part Numbers
DS3 NIU3 3-Slot Shelf
NIU3
Blank slot cover
Power Supply/Rectifier
Relay Replacement Kit
(1 Alarm Relay, 2 Signal
Relays, 2 Jumper Straps)
Wallmount Brackets:
3-Slot Shelf
12-Slot Shelf
1212073L1
CLEI: NCM5K4ZD _ _
1213075L2
CLEI: NCD3EGRA _ _
1212076L1
1212080L1
1212072L1
1212073L1WM
1212078L1WM
